The rhesus monkeys have been used to access a gene transduction efficiency in non-human primate model. Pseudotyping using the vesicular stomatitis virus G envelope protein has not increased transduction efficiency. CD4-enriched lymphocytes transduced with a retroviral vector that incorporates the gibbon ape leukemia virus envelope protein express aTat/Rev gene and are associated with reduced pathogenic events normally observed during early simian immuno-deficiency virus infection.